Desenvolvimento de tecnologia avançada de fermentação para a produção de butanol, isopropanol e etanol a partir de bagaço de cana-de-açúcar

Author(s)

Carla Ferreira dos Santos Vieira

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Química
• Defense date: 2020-10-30

Examining board members

Adriano Pinto Mariano; Ariovaldo José da Silva; Carlos Eduardo Vaz Rossell; Rafael Ramos de Andrade

• Advisor: Adriano Pinto Mariano; Francisco Maugeri Filho

Abstract

Biobutanol is conventionally produced through ABE (acetone-butanol-ethanol) fermentation. However, acetone¿s corrosivity and poor fuel properties decrease attractiveness of this process for butanol production as biofuel. Alternatively, the production of biobutanol through IBE (isopropanol-butanol-ethanol) fermentation decreases these market risks since the IBE mixture can be used directly as fuel or as gasoline additive. However, technical limitations commonly found in ABE fermentation, i.e. low productivities, high product inhibition, and high sensitivity towards fermentation inhibitors from second generation processes, are even more accentuated in IBE fermentation. Thus, this thesis proposed the integration, in the same fermentation vessel, of a cell immobilization system, which increases the number of cells inside the bioreactor, and the vacuum extraction technology, that promotes in-situ product recovery, decreasing product inhibition. 3D printing technology was used to build the immobilization system, composed by a cage-like prototype that maintained the sugarcane bagasse in contact with the fermentation medium along the process. This thesis also proposed a strategy to enable IBE production from sugarcane bagasse hydrolysates using molasses as supplement. The immobilization system allowed the performance of five consecutive batches (138 hours) in synthetic medium. However, glucose conversion and IBE productivity were limited to 37 % and 0.21 g/L?h, respectively. Coupling vacuum technology to the system allowed the conduction of 209 hours of repeated-batch process; glucose conversion and IBE productivity increased to 66 %, 0.28 g/L?h, respectively. At the end of the fermentation, we obtained a condensate with 29 g butanol/L; this higher butanol concentration compared to concentrations achieved inside the bioreactor can decrease energy consumption during separation process. Parallelly, this thesis showed that, despite the presence of fermentation inhibitory compounds, the use of sugarcane bagasse lignocellulosic hydrolysates is feasible for IBE production, specially when molasses is added as supplement. Glucose was exhausted and sucrose, xylose, and lactic acid consumption were 38 %, 31 %, and 69 %, respectively. We thank the São Paulo Research Foundation (FAPESP) for the financial support (Grant numbers 2015/20630-4; 2016/23042-9; 2017/07390-0, and 2018/23983) (AU)

• FAPESP's process: 16/23042-9 - Development of advanced fermentation technology for the production of n-butanol, isopropanol and ethanol from sugar cane bagasse
• Grantee: Carla Ferreira dos Santos Vieira
• Support Opportunities: Scholarships in Brazil - Doctorate